Objects in JavaScript

An object is a dynamic data structure that stores related data as key-value pairs, where each key uniquely identifies its value.

• The values of properties can be primitives, objects, or functions (known as methods when defined inside an object).
• Objects are mutable and dynamic properties can be added, modified, or deleted at any time.
• Objects allow data grouping and encapsulation, making it easier to manage related information and behaviour together.

Object Literal

An object literal "literally" describes an object using a concise syntax with zero or more key:value pairs inside curly braces to describe all the object properties:

  {  firstName:"John",
     lastName:"Doe", 
     age:50,
     eyeColor:"blue"}

Note : You should declare objects with the const keyword.

There are two primary ways to create an object in JavaScript:

1.Creation Using Object Literal

The object literal syntax allows you to define and initialize an object with curly braces {}, setting properties as key-value pairs.

      let obj = {
         name: "vidhya",
         age: 23,
         job: "Developer"
      };
     console.log(obj);

2.Creation Using new Object() Constructor

     let obj = new Object();
     obj.name= "Alex",
     obj.age= 4,
     obj.job= "WatchMan"

     console.log(obj);

Basic Operations on JavaScript Objects

1. Accessing Object Properties

You can access an object’s properties using either dot notation or bracket notation

    // Using Dot Notation
     console.log(obj.name);

    // Using Bracket Notation
     console.log(obj["age"]);

1. Modifying Object Properties

Properties in an object can be modified by reassigning their values.

 let obj = { name: "vidhya", age: 23 };
 console.log(obj);

 obj.age = 25;
 console.log(obj);

1. Adding Properties to an Object

You can dynamically add new properties to an object using dot or bracket notation

1. Removing Properties from an Object

The delete operator removes properties from an object.

1. Checking if a Property Exists

You can check if an object has a property using the in operator or hasOwnProperty() method.

1. Iterating Through Object Properties

Use for...in loop to iterate through the properties of an object.

1. Merging Objects

Objects can be merged using Object.assign() or the spread syntax { ...obj1, ...obj2 }.

1. Object Length

You can find the number of properties in an object using Object.keys().

Reference :

Objects in JavaScript - GeeksforGeeks

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